ANT101H5 Chapter Notes - Chapter 2: Georges Cuvier, Binomial Nomenclature, Carl Linnaeus

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CHAPTER 2: THE DEVELOPMENT OF EVOLUTIONARY THEORY (PGS. 19-36)
Learning Objectives
Describe the key contributions to evolutionary theory made by precursors to Darwin and
explain how each influenced the development of evolutionary theory
Explain how natural selection works
Contrast the scientific understanding of biological evolution with nonscientific approaches
that seek to explain the origins of life and how life has changed on earth
Introduction
The earliest human ancestors evolved from a species that lived some 5 to 8 million years ago
The ancestral species was the last common ancestor we share with chimpanzees
The lineage that led to the apes and ourselves separated from a monkey-like ancestor some
20 mya, and monkeys are still around b/c as lineages diverged from a common ancestor,
each group went its separate ways
Each living species is the current product of processes that go back million of years
We aren’t able to see evolution since it takes long periods of time, but we do see
microevolutionary changes in many species
Evolution is a theory, one that has increasingly been supported by a mounting body of
genetic evidence
As physical anthropology is concerned with all aspects of how humans came to be and how
we adapt physiologically to the external environment, understanding details of the
evolutionary process is crucial
A Brief History of Evolutionary Thought
Charles Darwin was the first person to explain the basic mechanics of the evolutionary
process
Natural Evolution the most critical mechanism of evolutionary change, first articulated by
Charles Darwin
o Refers to genetic change in the frequencies of certain traits in populations due to
differential reproductive success between individuals
Alfred Russel Wallace independently reached the same conclusion as Darwin did more or
less the same time about natural selection
It was generally accepted that all life on earth been created by God exactly as it existed in the
present, and the belief that life-forms couldn’t change came to be known as fixity of species
Fixity of Species the notion that species, once created, can never change
o An idea diametrically opposed to theories of biological evolution
Evolution requires time, and the idea of immense geological time, which today we take for
granted, simply didn’t exist
The Scientific Revolution
For Europeans, the discovery of the New World and circumnavigation of the globe in the
fifteenth century overturned some basic ideas of earth (Ie. The Planet is not flat)
As the Europeans began to explore, their awareness of biological diversity was greatly
expanded as the became aware of plants, animals they hadn’t seen before
Later Copernicus challenged the notion of Aristotle (the earth is circled by the sun, moon and
stars)
o Indian scholars figured out that the sun was the center of the solar system before
Corpernicus
o Corpernicus is generally credited with removing the earth as the center of all things
Galileo Falilei restated Corpernicus theory later (since at the time it didn’t attract anyone)
Precursors to the Theory of Evolution
Scholars were increasingly impressed with the amount of biological diversity they saw
John Ray
In the 1700s, developed the concept of species
First to recognize that groups of plants and animals could be distinguished from other
groups by their ability to mate with one another and produce offspring
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Notes From Reading
CHAPTER 2: THE DEVELOPMENT OF EVOLUTIONARY THEORY (PGS. 19-36)
Placed groups of reproductively isolated organisms into a single category, species
Also recognized that species frequently shared similarities with other species, and he
grouped these together in a second level of classification, genus
Was the first to use the labels genus and species (which is still used today)
Carolus Linnaeus
Developing a method of classifying plants and animals
Standardized Ray’s use of genus and species
Binomial Nomenclature in taxonomy, the convention established by Carolus Linnaeus
whereby genus and species names are used to refer to species
o Homo sapiens refer to human beings
Added two more categories: class and order
Taxonomy the branch of science concerned with the rules of classifying organisms on the
basis of evolutionary relationships
Jean-Baptiste Lamarck
Was the first to explain the evolutionary process
Suggested a dynamic relationship between species and the environment changed, an
animal’s activity patterns would also change to accommodate the new circumstances
The physical changes would occur in response to bodily “needs” so that if a particular part of
the body felt a certain need, “fluids and forces” would be directed to that point and the
structure would be modified
Theory is known as the inheritance of acquired characteristics or he use disuse theory
o According to this theory, a trait acquired by an animal during its lifetime can be
passed on to offspring
It is wrong, only those traits that are influenced by genetic information contained within sex
cells (egg and sperm) can be inherited
He coined the term biology to refer to studies of living organisms
Georges Cuvier
Introduced the concept of extinction to explain the disappearance of animals represented by
fossils
Suggested a variation of a theory known as catastrophism
Catastrophism the view that the earth’s geological landscape is the result of violent
cataclysmic events
o This view was promoted by Cuvier, especially in opposition to Lamarck
Curvier needed to account for the emerging fossil evidence that organisms had become more
complex over time
He suggested that after each disaster, the incoming migrants had a more modern appearance
because they were the results of more recent creation events
Thomas Malthus
Wrote An Essay on the Principle of Population, which inspired both Darwin and Wallace in
their separate discoveries of natural selection
In his essay, he argued for limits to human population growth
o Pointed out that human population could double in size every 25 years
Warned that increased numbers of humans would eventually lead to famine
Darwin and Wallace accepted Malthus’ proposition that population size increases
exponentially while food supply remains constant (and all organisms)
What Malthus didn’t realize (whereas Darwin and Wallace did) was the competition for the
available resources
Competition between individuals is the ultimate key to understanding natural selection
Charles Lyell
Founder of modern geology
Argued that geological processes observed in the present are the same as those that
occurred in the past
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